XC886/888CLM
Bootstrap Loader
User’s Manual
18-6
V1.3, 2010-02
Bootstrap Loader, V1.0
18.1.1.3
Response Code to the Host
The microcontroller would let the host know whether a block has been successfully
received by sending out a response code.
tabulates the possible responses from the microcontroller upon reception of
a Header, Data or EOT block for each working mode.
If a block is received correctly, an Acknowledge Code (55
H
) is sent. In case of failure, it
may be a wrong block type error or checksum error. Block type error is caused by two
conditions; (i) The microcontroller receives a block type other than the implemented
ones; (ii) The microcontroller receives the transfer blocks in wrong sequence. In both
error cases, the BSL routine awaits the actual block from the host again.
When program and erase operations of Flash are restricted due to Flash Protection
Mode 0 or 1 being enabled, protection error code will be sent to the host. This will
indicate that Flash is protected, and hence, it cannot be programmed or erased. In this
error case, the BSL routine will wait for the next header block from the host again.
Table 18-4
Possible Responses for Various Block Types
Mode Header Block
Data Block
EOT Block
0, 8
Acknowledge, Block Error,
Checksum Error, Protection
Error
Acknowledge, Block
Error, Checksum Error
Acknowledge, Block
Error, Checksum Error
1, 9
Acknowledge, Block Error,
Checksum Error
-
-
2
Acknowledge, Block Error,
Checksum Error, Protection
Error
Acknowledge, Block
Error, Checksum Error
Acknowledge, Block
Error, Checksum Error
3
Acknowledge, Block Error,
Checksum Error
-
-
4
Acknowledge, Block Error,
Checksum Error, Protection
Error
-
-
6
Acknowledge, Block Error,
Checksum Error, Protection
Error
-
-
A
Acknowledge, Block Error,
Checksum Error
-
-
F
Acknowledge, Block Error,
Checksum Error
-
-
*